Power operated toothbrush



May 19, 1964 K. GERBER ETAL POWER OPERATED TooTHBRUsH Filed July 30, 1962 NN ww MN .4,

United States Patent Oilice 3,133,297 POWER OPERATED TOOTHBRUSH Karol Gerber, Cudahy, and Charles T. Govin, Wauwatosa, Wis., assignors, by mesne assignments, to Henry Windward, Milwaukee, Wis.

Fiied .luly 3i), 1962, Ser. No. 213,344 8 Claims. (Cl. 1522) The invention relates to a dental device and more particularly to a power driven toothbrush.

Vibrating or power driven toothbrushes have been used to some extent in the past for gum massage and tooth Cleaning. However, the usual type of vibrating toothbrush is a cumbersome and heavy article due to the fact that the motor is included within the casing. Because of the weight and size of the device, it is often difficult and inconvenient to handle, particularly for children.

The present invention is directed to a lightweight power driven toothbrush which incorporates an improved drive system and a simplied attachment of the exible drive cable to the toothbrush. More specifically, the toothbrush includes an outer casing, and a stem which carries the brush is partially located Within the casing and pivotally connected to the casing walls. The stem is provided with a thin dimension in a direction parallel to the axis of pivotal connection and is `flexible in that direction. However, the stem is provided with a relatively thick dimension perpendicular to the axis of pivotal connection so that the Vstein will be relatively stiff in that i.

direction.

The inner end of the stem is connected to an eccentric and the eccentric drives the inner end of the stem in a rotary or circular path of movement. By virtue of the flexible nature of the stem in one direction, the outer end of the stern carrying the brush will be provided with an oscillating motion in a single plane extending perpendicular to'the axis of the pivotal connection.

The motor or power unit is mounted on a wall or other object and is connected to the eccentric in the casing by a helically woundV coil spring. One end of the coil spring is engaged with the drive shaft of the motor while the other end is connected to a stub shaft which is secured to the eccentric. On operation, the coil spring winds tightly around the shafts to provide a positive, yet readily detachable, drive connection.

As the motor, which drives the toothbrush, is not located within the casing, but is connected to the toothbrush by a flexible coil spring which functions as a drive shaft, the unit is lightweight and can be readily and conveniently handled and maneuvered. f

The movement provided by the stem is an oscillating motion in a singel plane which enables the bristles of the brush to remove food particles from between the teeth and provide the proper massaging action for the gums.

The unit has a minimum number ofrmoving partsand no precise tolerances are required so that manufacturing and assembly costs are minimized.

Other objects and advantages will appear in the course of the following description.

In the drawings:

FIG. 1 is a longitudinal section of the toothbrush and motor of the invention;

FIG. 2 is an enlarged longitudinal section of the drive connection between the motor and the drive stem;

3,133,297` Patented May 19, 1964 FIG. 3 is a transverse section taken along line 3 3 of FIG. 1; and

FIG. 4 is a view taken along line 4-4 of FIG. 1.

The drawings illustrate a power-dn'ven toothbrush which comprises an outer casing 1 having a stem 2 pivotally connected to the casing wall by a pin 3. As best shown in FIG. 4, the stem is provided with a pair of opposite projections 4 which are located in substantial engagement with the inner Wall of the Casing and the pin 3 extends through aligned openings in the stem and casing to mount the stem for pivotal movement.

The outer end 5 of the stem 2 is reduced in diameter and is received within an axial recess 6 formed in the inner end of a brush 7. The outer end 5 is wedged within the recess 6 to firmly connect the brush to the stem. To maintain alignment of the brush with respect to the pivotal movement of the stein, the end 5 is provided with a pair of projections 8 which are located within a slot 9 formed in the end of the brush. Other structures for maintaining alignment of the stern and brush can be used in place of the projections 8 and slots 9.

A flexible sleeve 1t) is secured to the casing 1 and stem 2 and covers the joint between the members.

As best shown in FIGS. 1 and 4, the central portion 11 of the stern is provided with a relatively thin dimension in a direction parallell to the axis of pin 3, which permits the stem to ex or bend in that direction. The central portion 11 has a substantially wider dimension in a direction perpendicular to the axis of pin 3 so that the stern will not ex in that direction. j

To drive the stem 2, the inner end 12 of the stem is rounded and is located within a generally circular recess 13 formed in an eccentric spool 14. As bestY shown in FIG. 3, the recess 13 is located out of alignment with the axis of the spool 14, so that as the spool rotates, the end 12 of stem 2 is provided with a generally circular or rotary motion.

Due to the flexible nature of the stem 2 in a direction parallel to the axis of pin 3, the rotary motion of the inner end 12 of the stem will be transformed to an oscillating motion of the brush 7 in a single plane perpendicular to the axis of pin 3 as shown by the arrows in FIG. l. This design of the stem 2 provides a very simple and effective means of transforming the circular motion of the eccentric or drive member into the straight line motion which is most desirable for the brushing of teeth.

The outer surface of the eccentric spool 14 is provided with a pair of ridgeswhich are disposed generally in engagement with the inner Wall of the casing and provide a bearing surface for the rotation of the spool. In addition, the spool is provided with an axial recess 16 and a stub shaft 17 is secured or keyed within the recess 16. The shaft 17 extends through an axial opening 18 in an end cap 19 which is threaded onto the inner end of the casing 1.

To rotate the eccentric spool 14, one end of a helically wound coil spring 20 is wedgingly engaged with the outer end of shaft 17. Shaft 17 may be provided with a slight taper to insure a firm wedging contact between the members. The spring 20 is enclosed within an outer sheath 21 formed of plastic or other flexible material .and a metal -ferrule 2.2 is secured by an adhesive or the like to the end of the sheath 21 and bears against the shoulder 23 formed inthe end cap 19.

The opposite end of the spring Ztl is wedgingly engaged with the outer end of a motor shaft adapter 24 which is secured to the motor shaft 25. A ferrule 26 is secured to the corresponding end of the sheath 2l and bears against a shoulder 27 formed in a sleeve 28 secured to a motor casing 29. The sleeve 28 is secured within an opening in the casing 29 by a retaining nut 36 which is threadedly engaged with the sleeve.

F[he spring provides a positive, yet readily detachable, connection between the motor drive shaft adapter 24 and the shaft 17. The spring 2t) is wedged into contact with the respective members and rotation of the spring is `in a direction to wind itself on the respective shafts and cinch the spring to the shafts. The spring can be readily removed from the adapter 24 or the stub shaft i7, by merely unwinding or backing the spring off of the shafts. In some cases the adapter 24 can be eliminated and the spring 20 can then be attached directly to the motor shaft 25.

As the motor which drives the toothbrush is not located within the toothbrush casing, but is mounted on the wall or on other outside objects and is connected to the casing by the flexible spring 20, the toothbrush unit itself is lightweight and can be readily and conveniently handled even by children. Moreover, the coil spring 20 can be easily detached from either the motor or the toothbrush so that individual elements can be conveniently stored or packaged for traveling.

The toothbrush of the invention has a minimum number of moving parts, and this feature is particularly important for commercial production of a vibrating or power-drive toothbrush of this type. Moreover, the tolerances involved are not critical, for the eccentric spool and stem merely float within the outer casing and no precise machining is required for the elements.

While the stem 2 is shown as being straight, it is contemplated that the stem can be curved for use in a casing that is correspondingly curved `for styling purposes or for increased maneuverability.

Various modes of carrying out .the invention are contemplated as being within the scope of the yfollowing claims particularly pointing out .and distinctly claiming the subject matter which is regarded as the invention.

We claim:

l. A power-driven apparatus, comprising an outer casing, a unitary stem pivotally supported within said casing and having an outer end -extending outwardly of the casing, an operating member secured to the outer end of said stem, means for driving the inner end of the stem in a generally circular path of movement, and means associated with the portion of the stem extending between the inner end thereof and the position of pivotal connection to the casing for transposing said circular motion of the inner end to an oscillatory motion of the outer end in a single plane.

2. A power-drive apparatus, comprising an outer casing, a unitary stem mounted within said casing for pivotal movement and having `an outer end extending outwardly of the casing, an operating member secured to the outer end of said stem, a rotating member mounted for rotation within the casing and having an eccentric recess therein, the inner end of said stem being received with-in said eccentric recess to thereby provide the inner end of said stern with a generally circular path of movement, -means for rotating said rotary member, and means associated with the stem and located between said inner end and the location of pivotal connection to the casing for transposing said circular motion of the inner end -to an oscillatory movement of the outer end in a single plane.

'3. A power-driven toothbrush, comprising an outer casing, a stem pivotally supported within said casing and having an outer end extending outwardly of the casing, a brush member secured to the outer end of said stem, and means for driving the inner end of the stem in a generally circular path of movement, the portion of the stem located between the inner end thereof and the position of pivotal connection to the casing having a substantially greater dimension in a direction perpendicular to the axis of pivotal connection than in a direction parallel to said axis to thereby prevent said stem from exing in a `direction perpendicular to said axis and permitting said stem to hex in a direction parallel to said axis.

4. A power-driven toothbrush, comprising an outer casing, a stem pivotally connected within the casing and having an outer end portion extending outwardly of the casing, a brush member attached to said outer end portion of the stem, said stem having a substantially greater dimension in a direction perpendicular to the axis of pivotal connection to the casing than in a direction parallel to said axis, and means for driving the inner end of the stem in a generally circular path of movement with said flexible nature of the stem in one direction transposing said circular movement of said inner end to an oscillating movement for said outer end portion in a single plane.

5. A power-driven toothbrush, comprising an outer casing, a unitary stem located within the casing and pivotally connected to the casing, said stem having an outer end extending outwardly of the casing, a brush member secured to the outer end of the stem, a rotating member mounted for rotation within the casing and having a recess in an end surface facing longitudinally of the casing with said recess being located out `of alignment with the axis of said rotating member, a stub shaft secured to the opposite end siuface of said rotating member and located axially of said member, the inner end of said stem being received within said recess to thereby provide the inner end of the stem with a generally circular path of movement as said rotating member is rotated, power means, and a iiexible drive member connecting said power means to said stub shaft, the portion of the stem located between the inner end thereof and the position of pivotal connection to said casing being stiif in a direction perpendicular to said axis of pivotal connection and being exible in a direction parallel to said aXis to thereby transpose said circular motion of the inner end of the stem to an oscillating motion in a single plane for the outer end and said brush member.

6. A power-driven toothbrush, comprising an outer casing, an elongated stem disposed within the casing, a pin pivotally connecting the central portion of the stem to the casing, a brush member secured to the outer end of the stem and located outwardly of the casing, a rotating spool journalled for rotation within the casing, means to eccentrically connect the inner end of the stem to the rotating member to thereby provide .the inner end of the stem with a generally circular path of movement, a driven shaft connected to said spool, a motor located outside of the casing and having a drive shaft, and a helically wound coil spring having one end engaged with said driven shaft and having the opposite end engaged with the drive shaft to thereby transmit rotation of the drive shaft to said `driven shaft, a portion of the stem located between the inner end thereof and said pin being stiff in a direction perpendicular to the axis of the pin and being flexible in a direction parallel to said axis to thereby transpose the circular motion of said inner end to an oscillating motion in a single plane for the outer end of the stem.

7. A power driven toothbrush comprising, a casing, a stem pivotally supported within said casing and having an outer end portion extending outwardly of the casing, a brush member attached to said outer end portion of the stem, said stem being flexible in a rst plane parallel to its length but relatively rigid in a second plane that is parallel to its length and perpendicular to the first plane, and means for driving the inner end of the stem in a substantially circular path of movement whereby the flexible characteristic of said stem in one direction serves to transpose :the circular movement of said inner end to `an osciiiating movement of said outer end portion t0 actuate Isaid brush member.

8. A power driven toothbrush comprising, a casing, a stem pivotaiiy supported Within said casing and having an outer end portion extending outwardly o the casing, a brush member attached to said outer end portion of the stem, said stem being flexible in a direction parallel to the .axis of pivotal connection to the casing and being reiativeiy rigid in a direction perpendicular .to the axis of pivotal connection to the casing, and means for driving the inner end of the stem in a substantally circular path of movement whereby the flexible characteristic of said stem in one direction serves to transpose the circular movement of said inner end to an oscillating movement ofsaid outer end portion to aotuate said brush member.

References Cited in the file of this patent UNITED STATES PATENTS 1,832,519 Wheat et al Nov. 17, 1931 1,945,616 Mastrud KFeb. 6, 1934 2,596,335 Kessler May 13, 1952 2,747,384 Beam May 29, 19'56 2,904,804 Odessey Sept. 22, 1959 3,029,651 Flatt Apr. 17, 1962 

1. A POWER-DRIVEN APPARATUS, COMPRISING AN OUTER CASING, A UNITARY STEM PIVOTALLY SUPPORTED WITHIN SAID CASING AND HAVING AN OUTER END EXTENDING OUTWARDLY OF THE CASING, AN OPERATING MEMBER SECURED TO THE OUTER END OF SAID STEM, MEANS FOR DRIVING THE INNER END OF THE STEM IN A GENERALLY CIRCULAR PATH OF MOVEMENT, AND MEANS ASSOCIATED WITH THE PORTION OF THE STEM EXTENDING BETWEEN THE INNER END THEREOF AND THE POSITION OF PIVOTAL CONNECTION TO THE CASING FOR TRANSPOSING SAID CIRCULAR MOTION OF THE INNER END TO AN OSCILLATORY MOTION OF THE OUTER END IN A SINGLE PLANE. 